﻿// Copyright © 2004, 2011, Oracle and/or its affiliates. All rights reserved.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;

using System.Data.Common;
using System.Data;

namespace MySql.Data.MySqlClient
{
	/// <summary>
	/// BaseCommandInterceptor is the base class that should be used for all userland 
	/// command interceptors
	/// </summary>
	public abstract class BaseCommandInterceptor
	{
		protected MySqlConnection ActiveConnection { get; private set; }

		public virtual bool ExecuteScalar(string sql, ref object returnValue)
		{
			return false;
		}

		public virtual bool ExecuteNonQuery(string sql, ref int returnValue)
		{
			return false;
		}

		public virtual bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
		{
			return false;
		}

		public virtual void Init(MySqlConnection connection)
		{
			ActiveConnection = connection;
		}
	}

	/// <summary>
	/// CommandInterceptor is the "manager" class that keeps the list of registered interceptors
	/// for the given connection.
	/// </summary>
	internal sealed class CommandInterceptor : Interceptor
	{
		bool insideInterceptor = false;
		List<BaseCommandInterceptor> interceptors = new List<BaseCommandInterceptor>();

		public CommandInterceptor(MySqlConnection connection)
		{
			this.connection = connection;

			LoadInterceptors(connection.Settings.CommandInterceptors);
		}

		public bool ExecuteScalar(string sql, ref object returnValue)
		{
			if (insideInterceptor) return false;
			insideInterceptor = true;

			bool handled = false;

			foreach (BaseCommandInterceptor bci in interceptors)
				handled |= bci.ExecuteScalar(sql, ref returnValue);

			insideInterceptor = false;
			return handled;
		}

		public bool ExecuteNonQuery(string sql, ref int returnValue)
		{
			if (insideInterceptor) return false;
			insideInterceptor = true;

			bool handled = false;

			foreach (BaseCommandInterceptor bci in interceptors)
				handled |= bci.ExecuteNonQuery(sql, ref returnValue);

			insideInterceptor = false;
			return handled;
		}

		public bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
		{
			if (insideInterceptor) return false;
			insideInterceptor = true;

			bool handled = false;

			foreach (BaseCommandInterceptor bci in interceptors)
				handled |= bci.ExecuteReader(sql, behavior, ref returnValue);

			insideInterceptor = false;
			return handled;
		}

		protected override void AddInterceptor(object o)
		{
			if (o == null)
				throw new ArgumentException(String.Format("Unable to instantiate CommandInterceptor"));

			if (!(o is BaseCommandInterceptor))
				throw new InvalidOperationException(String.Format("Resources.TypeIsNotCommandInterceptor",
				  o.GetType()));
			BaseCommandInterceptor ie = o as BaseCommandInterceptor;
			ie.Init(connection);
			interceptors.Insert(0, (BaseCommandInterceptor)o);
		}

		protected override string ResolveType(string nameOrType)
		{
			return null;
		}

	}

}
